Well finally seen one in action, check it out at http://www.renewability.com/powerpipe.htm
I don’t know much about these systems,but I can’t imagine getting much heat from a drain pipe. I would guess that much of the effectiveness comes from the localized savings of energy that is apparent in the water heater. Do they have any information on whole house energy consumption with these in place?
My concern is that with much exposed copper surface area, the majority of the heating is coming from the cold water inside these lines absorbing heat from the conditioned space of the house and not so much from the drains. this would lead to an increase in the amount of energy consumed by the heating device of the home. Besides if one were going to install these wouldn’t it be more effective to place the wraps around horizontal sections of pipe(where the heated water is in most direct contact with the inner pipe surface) rather than vertical sections (where a lot of the water is free falling through the lumen of the drain?
My concern also but one could always insulate the outside of this pipe heat exchanger. As for the horizontal/vertical position, it was my taught also that it would be better installed on the horizontal…but from reading further, it appears that the vertical installation is better…
But the biggest concern is: how long it would take for an average homeowner to recuperate the cost of this gadget (~$1000) before any savings is achieved…
A lot of variables…it only recovers heat during showers and leaving the water running when washing your hands (LOL)!!! In all other hot water draws, the water is held, used and then drained when no cold water is running to the hot water tank.
In a larger new home with 2-3 baths with showers, a lot of excellent drain design will have to be done to get all showers to drain to 1 waste stack or you buy an extra unit or 2. I see a lot of basements finished with a shower for bedrooms located there…how much will it cost to recover that heat?
The best place for these are barracks, dorms, gyms and other commercial, institutional, industrial quick payback locations.
If the price comes down with volume production and there are good subsidies (instead of giving oil companies tax breaks called “depletion allowances”; we drained the oil field …poor us!), maybe it will become a decent home investment.
Want to save $$$ on hot water, use less…cold water washes, low flow showerheads, not having more than 1 shower per day (most times I only need a shower every 2-3 days; not that active on HI’s).
Below copied from: http://en.wikipedia.org/wiki/Drain_water_heat_recovery
Hot water heat recycling
From Wikipedia, the free encyclopedia
A typical unit in the basement of a family home.
Hot water heat recycling (also known as drain water heat recovery, greywater heat recovery, or sometimes shower water heat recovery) is the use of heat exchanger technology to recover and reuse hot water heat from various activities such as dishwashing, clothes washing and especially showers. The technology is used to reduce primary energy consumption for domestic water heating while also reducing greenhouse gases. Standard units save up to 60% of the heat energy that is otherwise lost down the drain when using the shower.
The technology is fully recognized in Canada where the federal ecoENERGY retrofit for homes program offers grants for installations and the EnerGuide for New Houses program has energy savings and energy credit calculations that it uses for new home construction.
*The gent that essentially has my old job in energy here, questions the grant being given for homes for this technology at this time. *
I’ve only seen them on new homes that were sold with the eco energy tag. They don’t cost anything to run, so I don’t see the issue with it.
If a client wants to install one they can have an energy audit done and recover some of the cost through the EcoEnergy Program…
Certified Energy Auditor
Did they have an outer insulation layer/system installed so they don’t take house heat to warm the water?
You might get more info by calling toll free: 1-877-606-5559
When you flush the toilet, water being discharge down the drain already used heat from the house to reach ambient temperature; this heat exchanger is recuperationg heat that is going down the drain to pre-heat water used to refill the toilet tank. That’s if you install the heat exchanger as per manufacturer’s recomendations that is to the whole house cold supply and not the WH supply only.
It may even recuperate some of the body heat being flushed in the process:mrgreen:…
Over $1000 for the 4’ dia. 5 ft. model.
I don’t think I’ll be installing one anytime soon.
But I think all the those who insist on being “green” should be forced to buy one to save mother earth.
Even if they take some of the home’s heat, at least it is recovered instead of just lost to the outside of the home. So I see 2 benefits. Any heat captured will be radiated right back into the room by the downstream pipes.
Remember the flush is one large surge of water with the time of the flush not being fully coincident with the time of the fill…this is what is needed to recover some of this parisitic heat loss from the house.* In this situation, it isn’t happening.
- When working as energy analyst for the Gov here, I calculated that the parasitic heat loss just from toilet flushing in a family of 4 with electric heat was about $115/year. Figures I used were: water comes in at 48-50 deg F and leaves at 70F.; electricity was $0.083/kWh. This would be much better now as water saving tanks are not only saving water but a bit more energy also.
So what you’re saying is that this system will not produce a reasonable pay back on investment for residential application?
IMO, not unless you have several children taking 20+ minute showers!!! I’m not rushing out to buy one.
Here are some selected text from researchers:
OAK RIDGE NATIONAL LABS (ORNL):
Multifamily buildings with large hot water consumption patterns are an ideal application for the GFX. In cases where hot water is provided by resistance water heaters, operating cost savings should be sufficient to justify GFX installation with short simple payback times. The payback time for a specific
application obviously depends on installed cost, the amount of hot water consumed daily and the cost for delivering hot water using the conventional water heater.
FEDERAL ENERGY MANAGEMENT PROGRAM:
[FONT=Times New Roman]"To capture heat from wastewater produced by all sources in a dwelling and put it to use would require a regenerator-type, double-walled heat exchanger—**one that can capture heat from wastewater generated by one fixture or *appliance (e.g., a clothes washer) and apply this heat to assist another hot water demand that may occur at a later time."
“The impact on overall hot water energy consumption depends on the fraction of total hot water consumption that simultaneously produces warm rainwater. Good candidates for GFX application in the Federal sector would be dormitories and barracks, health facilities, and commercial and industrial facilities that produce waste heat that could otherwise be used for reheating water.”
[FONT=Times New Roman]“In general, buildings that require large amounts of hot water for showers (e.g., homes of families with several children, multifamily apartments, or barracks with showers on a common drain line) would be ideal candidates for the GFX and would lead to shorter paybacks.”
“In general, buildings that require large amounts of hot water for showers (e.g., homes of families with several children, multifamily apartments, or barracks with showers on a common drain line) would be ideal candidates for the GFX and would lead to shorter paybacks.”
But still a bay back, the builder here used seperate drains and in 2-4 bedroom homes.
You want to know where best to spend your $$$. Would a solar panel system be better if it could produce 60-70% of all hot water needed for a year at a system cost of $4,000; or would a system that recovers only 10-15% of all heat in hot water drained at a system cost of $1,200; or would a HP/AC unit with hot water heating, be better? I like the last one as it takes rejected heat (that you’re paying to get rid of anyways) from cooling and puts it into your hot water.
The ACEEE seems only to comment on this technology for industry:
[size=4]GFX drainwater heat recovery (cross-cutting)
*Very little of the heat in hot water is actually used; the vast majority of the energy goes down the drain after the **water is used for such tasks as crystal rinsing and drying applications . Economical recovery of the heat for **reuse has been a goal of many inventions over the years using various heat exchange and storage devices. The **GFX falling-film heat exchanger uses a vertical five-foot piece of 3" copper drainpipe wrapped with a spiral of **1/2" copper water supply pipe. As the drain water from a shower falls down the drain it forms a falling film on **the inside surface of the drain. This results in very high exchange efficiency with the incoming water in the 1/2" **line with typical efficiencies on the order of 40 to 75 percent. This technology crosscuts many industrial **sectors, but has particular usage in process with relatively hot wastewater streams. The chemical and food *processing industries may benefit from the use of this technology. Precise energy savings are unknown.
*Nadel, S., L. Ranier, M. Shepard, M. Suozzo, and J. Thorne. 1998. *
*Emerging Energy-Saving Technologies and Practices for the Buildings Sector. Washington, D.C.: American Council for an Energy-Efficient *Economy.
More details on turning drain water into wealth from CMHC and NRC attached…